The invention is generally directed toward conveyance of streams of imbricated flat items, of so called scaled streams, i.e. conveyance of a large number of flat items such as printed products like newspapers or magazines arranged in line and partly overlapping in conveying direction. The method and device according to the invention serve for removing sections, individual items or groups of successive items, from such scaled streams.
Scaled streams such as, for example, laid out by rotation printing machines are a commonly used conveying formation and are also used in intermediate storing during further processing of printed products (e.g. intermediate storage of printed products in scaled formations wound up in rolls). Scaled streams of printed products or of other flat items are typically conveyed laying loosely on conveying supports such as conveying belts. For sections of a conveying distance, wherein due to a too steep gradient, conveyance of the loose formation is not possible, double belts are provided between which the scaled stream is held.
For longer conveying distances on complicated courses (gradients, curves, turns) usually the conveying means are equipped with holding means for holding a scaled stream from moving laterally or in any other direction. For this kind of held conveyance of a scaled stream clamping devices arranged on a transport device (e.g. transport chain) are applicable. Depending on the stiffness of the items forming the scaled stream, depending on the course of the conveying line and depending on the demand on the conveyance, the scaled stream is held on one side only or on both sides.
The distance between single clamping elements along the scaled stream is to be chosen such that each item in the scaled stream is held by at least one clamping element. If each item is held by more than one clamping element, the scaled stream forms a coherent belt. If each item is held by one clamping element, only the scaled stream actually consists of sections, whereby each section comprises a plurality of items and is held by one clamping element.
Conveying means equipped with holding means and suitable for conveying scaled streams are described in U.S. Pat. Nos. 2,861,674, 3,877,564 and 4,512,457.
A plurality of known methods are applied for removing individual items or groups of successive items from a loose scaled stream. From a scaled stream with the downstream edges of the product positioned on the upper side of the stream a single item is removed, for example, by gripping the downstream edge and pulling the item out of the stream by accelerating it. This kind of removal is described in the publication EP-0116015 (U.S. Pat. No. 4,577,855, F153). For removal of groups of successive items, the scaled stream is divided at the end of a pivoting part of the conveying support and the pivoting part of the conveying support is pivoted upwards and downwards in order to be connected to a farther conveying means for conveying away the stream section to be removed from the scaled stream. Once the section to be removed has passed the pivoting part of the conveying support, the scaled stream is divided again and the conveying support is pivoted back.
It is an object of the invention to create a method and a device that allow removal of sections from scaled streams being held during conveyance. According to the present invention, an effect of the removal on the held conveyance of the stream parts not being removed is prevented as far as possible and the method is to be able to be carried out with a simple device.
According to the inventive method, the scaled stream being conveyed in a held manner is conveyed through a removal region, whereby the held conveyance for stream sections not to be removed remains largely unchanged. For sections that are to be removed completely or from which items are to be removed, the holding means is deactivated, whereby such sections are freed from the hold of the holding means and become removable.
The device for carrying out the inventive method comprises a conveying means (first conveying means) for conveying the scaled stream in a held manner. This first conveying means is designed for conveying the scaled stream through a removing region on a first conveying path. At the entrance of the removing region, controlling means are arranged for a controlled de-activation of the holding means. The device further comprises a second conveying means that is arranged on the first conveying path (parallel to the first conveying means) at the entrance to the removal region. The second conveying means is driven in synchrony with the first conveying means and within the removal region being adjustable for either conveying on the first conveying path or for conveying on a second conveying path leading away from the first conveying path.
The second conveying means is designed for interaction with a different part of the items in the scaled stream than the part being acted on by the holding means of the first conveying means. The second conveying means is equipped for conveying a scaled stream either loosely or held.